The present invention relates generally to fuel systems for vehicles and, more particularly, to an electronic returnless fuel system for a vehicle.
It is known to provide a mechanical returnless fuel system for a vehicle, which includes a fuel delivery module, a fuel filter, a fuel pressure regulator, a fuel rail, and fuel injectors. In the mechanical returnless fuel system, a fuel pump of the fuel delivery module typically runs at the maximum flow at all times to deliver fuel to an engine of the vehicle. When the engine of the vehicle is turned off, the heat from the engine continues to heat the fuel rail and causes the pressure in the fuel rail to rise. The increased pressure causes the fuel pressure regulator to open and relieve the pressure by dumping the heated fuel into the fuel tank, which generates vapor in the fuel tank.
It is also known to provide an electronic returnless fuel system for a vehicle, which eliminates the pressure regulator and the attendant fuel tank vapor formation by providing a pressure relief valve to relieve the pressure and by controlling the speed of the fuel pump. An example of such an electronic returnless fuel system is disclosed in U.S. Pat. No. 5,237,975 to Betki et al. In this patent, a returnless fuel delivery control system regulates fuel rail pressure at the level needed for precise control of fuel mass flow to fuel injectors at both normal and elevated engine temperatures. Other examples of returnless fuel systems are disclosed in U.S. Pat. Nos. 5,379,741, 5,448,977, and 5,848,583. However, these systems suffer from large pressure changes during transient flow and slow response characteristics.
It is desirable to provide a new electronic returnless fuel system for a vehicle that reduces vapor generation and heat input into the fuel tank. It is also desirable to provide an electronic returnless fuel system for a vehicle that reduces excess fuel being recirculated in the fuel tank. It is further desirable to provide an electronic returnless fuel system with pressure control, variable pressure, improved response characteristics, and reduced current of the fuel pump. Therefore, there is a need in the art to provide an electronic returnless fuel system that meets these desires.
It is, therefore, one object of the present invention to provide an electronic returnless fuel system for a vehicle.
It is another object of the present invention to provide an electronic returnless fuel system for a vehicle that minimizes pressure changes during transient flow conditions.
It is yet another object of the present invention to provide an electronic returnless fuel system for a vehicle that reduces vapor generation and heat input in a fuel tank for a vehicle.
To achieve the foregoing objects, the present invention is an electronic returnless fuel system for a vehicle including a fuel pump to pump fuel from a fuel tank. The electronic returnless fuel system also includes a fuel rail fluidly connected to the fuel pump to distribute the fuel to an engine of the vehicle and a pressure transducer to sense pressure of the fuel from the fuel pump to the fuel rail. The electronic returnless fuel system includes a controller electrically connected to the pressure transducer and the fuel pump to control the pressure of the fuel from the fuel pump to the fuel rail at a set operating pressure. The electronic returnless fuel system further includes a pressure relief valve interconnecting the fuel pump and the fuel rail set a predetermined amount below the set operating pressure to leak fuel back into the fuel tank.
One advantage of the present invention is that an electronic returnless fuel system is provided for a vehicle. Another advantage of the present invention is that the electronic returnless fuel system replaces the fuel pressure regulator with a pressure transducer and controls fuel pressure by controlling a fuel pump of the fuel delivery module. Yet another advantage of the present invention is that the electronic returnless fuel system minimizes pressure changes during transient flow conditions. Still another advantage of the present invention is that the electronic returnless fuel system operates more efficiently than a mechanical returnless fuel system. A further advantage of the present invention is that the electronic returnless fuel system allows gerotor fuel pumps to be used because the continuous leak allows the fuel pump to run at a rate that prevents a pumping section of the fuel pump from binding.
Other objects, features, and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.